The assembly line was essential to the culmination of the industrial revolution. And a prerequisite for the assembly line was another greta innovation in manufacturing: interchangeable parts. Before that idea came along, every item had to be made by an individual craftsperson. With the advent of interchangeable parts, manufacturing, production, and repair simplified considerably. Complicated product and machines could be made at speed all over the world by relatively unskilled workers. Here’s more from Interesting Engineering:

The first testing ground for interchangeable parts by Whitney was demonstrated within firearm production.

Whitney took 10 of his interchangeable rifles before congress. While standing in front of the crowd, he disassembled all of them, mixed up al of the parts, and then reassembled them in working order. This would’ve been incredible at the time as everything prior was custom made.

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